1. Field of the Invention
This invention relates generally to apparatus for use in endoscopic photography but, more particularly, to apparatus by which a rapidly pulsable strobe, when used in combination with a particular type of automatic camera, can be successively fired a plurality of times over a predetermined interval so that when any camera of the type is used with the strobe at least part of at least one strobe pulse will occur during the camera's exposure cycle.
2. Description of the Prior Art
Endoscopes are optical viewing devices well known to the medical profession for their usefulness in diagnosing disease. With an endoscope, a physician, typically a surgical consultant, visually examines the interior of a patient's body organs for pathological processes whose presence is suspected or indicated by clinical and laboratory findings.
Once detected, a pathology is then carefully studied to determine its precise nature and extent so that the proper course of treatment can be decided upon and recommended to the patient.
For a variety of reasons, it is often advantageous for the surgical consultant to have a permanent photographic record of the endoscopic findings. Such records are useful, for example, for their educational value. Also, they can form part of the patient's permanent medical file or can be used as a basis for evaluating changes in the pathology. Additionally, endoscopic photographs serve as a powerful tool for promoting communication between the examining physician and others involved or interested in the diagnosis and as a means for informing the patient about the nature of his illness.
Although endoscopic photographs have their beneficial uses, they are somewhat difficult to obtain because the clinical form of most endoscopes generally is unsuitable for photography, because of the requirements of medically sound and safe practice, and because of the overriding concern for patient safety and comfort.
Photographic and optical principles, for instance, demand that any camera chosen for use with an endoscope must be able to be focused on the image provided by the endoscope's eyepiece, that adequate lighting be provided to assure acceptably exposed photographs, and that the examining physician, and sometimes more than one, be able to see an image of the field under examination immediately before and after a picture is taken in case of stills and continuously in the case of motion pictures. And all of this must be accomplished by apparatus which ideally shares the endoscope's single optical path.
Sound clinical procedure, on the other hand, imposes certain design constraints which make it difficult to satisfy the photographic and optical requirements for endoscopic apparatus. One major obstacle, for example, is the clinical desirability of using only one endoscope for both the visual clinical examination and the photographic work. It is neither convenient for the examining physician nor fair to the patient to have to withdraw the clinical endoscope once a pathology has been located, insert the photographic endoscope, photograph the field of interest, withdraw the photographic endoscope and reinsert the clinical endoscope. A process like this would obviously complicate an endoscopic examination by adding additional risk and discomfort to what is inherently an uncomfortable ordeal to begin with. Also, since the endoscope must be manipulated quite a bit throughout the examination, any photographic apparatus designed for use with the clinical endoscope should not hamper the physician's freedom of movement or require extensive operations involving attachment and detachment of the photographic apparatus with the endoscope.
Consequently, apparatus used for endoscopic photography must be easy to use, e.g. manipulate, must not unduly prolong the endoscopic examination, ideally should be mechanically and optically compatible with an existing form of clinical endoscope and, as well, must be capable of reliably reducing photographs which are acceptably exposed while containing adequate detail.
Finally, such apparatus must be absolutely safe and must, in particular, be free from any danger of causing electrical shock or creating unduly high temperatures which may come into contact with the patient.
Given the above general considerations, it is evident that the problems associated with providing apparatus for use in endoscopic photography are varied--involving both technical and humane considerations. In the past, these problems have been dealt with in a variety of ways by providing either specially designed photographic systems whose use is limited to endoscopic photography or by providing adapters by which existing cameras can be used with an existing endoscope. For examples reference may be had to U.S. Pat. No. 3,368,643 issued to John E. Hotchkiss on Feb. 1, 1972 and entitled "Endoscope For Photograpic Recording"; U.S. Pat. No. 3,918,072 issued to Toshihiro Imai et. al. on Nov. 4, 1975 and entitled "Single-Lens Reflex Optical System For An Endoscope"; U.S. Pat. No. 3,995,287 issued to Karl Storz on Nov. 30, 1976 and entitled "Endoscopic Camera"; U.S. Pat. No. 3,900,021 issued to Anthony Peter Walter Makepeace et. al. on Aug. 19, 1975 and entitled "Coupling For Endoscopes And Instruments Particularly Cameras"; U.S. Pat. No. 3,994,288 issued to Joseph G. Stumpf on Nov. 30, 1976 and entitled "Colposcope", and an article by Brian Stanford which appears in The Journal of Photographic Science, volume 3, 1955, and is entitled "Theoretical First Principles of Endoscopic Photography".
However, none of the foregoing publications appear to deal directly with the specific problem with which the present invention is concerned. In particular, the primary object of the present invention is to provide apparatus for use in endoscopic photographic work by which a well-known type of rapidly pulsable strobe when used in combination with a well-known type of automatic camera is successively fired a plurality of times over a predetermined interval so that, when the strobe is used with any one of the cameras from the well-known type to provide illumination of an endoscopic object field, at least part of one of the strobe pulses will occur during the camera's exposure cycle to assure adequate film exposure.
The prior art contains descriptions of apparatus by which an electronic flash unit can successively and repetitively be triggered to discharge either a plurality of capacitors or to discharge a single capacitor incrementally to provide adequate illumination in synchronization with the exposure cycle of a single camera. For examples of such apparatus reference may be had to U.S. Pat. No. 3,725,734 issued to Arthur Schneider on Apr. 30, 1973 and entitled "Electronic Flash Device"; U.S. Pat. No. 3,748,989 issued to Itsuki Ban on July 31, 1973 and entitled "Electronic Flash System"; and U.S. Pat. No. 3,438,766 issued to Conrad H. Biber on Apr. 15, 1969 and entitled "Electronic Flash Apparatus Having Variable Output". However, the apparatus of these disclosures appear to be responsive during a flash mode of operation of the camera to receiving a flash firing signal which occurs in synchronization with the opening of the camera shutter with which they are employed. For reasons which will become apparent in the description of the invention to follow, the type of camera with which the present invention is particularly useful provides no such signal in its ambient mode of operation which is the mode in which it is required to operate in its present application and therefore the above prior art apparatus would not provide the solution to the problem which is solved by the present invention.
It is also well known to operate the camera with which the present invention is used in its ambient mode of operation in combination with an electronic strobe such that the strobe is fired at a predetermined delay after the commencement of the camera photographic cycle. However, this operation provides no means of controlling the duration of the camera's exposure interval during its ambient exposure mode of operation while at the same time repetitively and successively firing an electronic strobe, all of which is a further object of the present invention.
Other objects of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the apparatus possessing the construction, combination of elements, and arrangement of parts which are exemplified in the following detailed disclosure.